A dinuclear complex [Dy(m-MBA)3phen]2-H2O was prepared by the reaction of DyCl3-6H2O, m-methylbenzoic acid and 1,10-phenanthroline in a 1:3:1 molar ratio, where m-MBA = m-methylbenzoate and phen = 1,10-phenanthroline. The complex was structurally characterized by single crystal X-ray diffraction, elemental analysis, UV and IR spectroscopy, molar conductance and TG-DTG techniques. It crystallizes in the monoclinic space group Cc with a =15.962(16), b = 18.505(18), c = 22.547(2) Ǻ; a = 90 °, β = 97.9820(10) °, y = 90°; z = 4. The unit cell contains a dinuclear molecule of the title compound. Each Dy(III) ion is eight-coordinated to one 1,10-phenanthroline molecule, one bidentate carboxylate group and four bridging carboxylate groups. The carboxylate groups are bonded to the dysprosium ions in two modes: chelating bidentate and bridging bidentate. The thermal decomposition process of [Dy(m-MBA)3phen]2-H2O has been followed by thermal analysis.